Abstract

Rice leaf folder, Cnaphalocrocis medinalis (Guenée), is one of the most serious pests on rice. At present, chemical control is the main method for controlling this pest. However, the indiscriminate use of chemical insecticides has non-target effects and may cause environmental pollution. Besides, leaf curling behavior by C. medinalis may indirectly reduce the efficacy of chemical spray. Therefore, it is crucial to cultivate efficient rice varieties resistant to this pest. Previous studies have found that three different rice varieties, Zhongzao39 (ZZ39), Xiushui134 (XS134), and Yongyou1540 (YY1540), had varying degrees of infestation by C. medinalis. However, it is currently unclear whether the reason for this difference is related to the difference in defense ability of the three rice varieties against the infestation of C. medinalis. To explore this issue, the current study investigated the effects of three rice varieties on the growth performance and food utilization capability of the 4th instar C. medinalis. Further, it elucidated the differences in defense responses among different rice varieties based on the differences in leaf physiological and biochemical indicators and their impact on population occurrence. The results showed that the larval survival rate was the lowest, and the development period was significantly prolonged after feeding on YY1540. This was not related to the differences in leaf wax, pigments, and nutritional components among the three rice varieties nor to the feeding preferences of the larvae. The rate of superoxide anion production, hydrogen peroxide content, and the activity of three protective enzymes were negatively correlated with larval survival rate, and they all showed the highest in YY1540 leaves. Compared to other tested varieties, although the larvae feeding on YY1540 had higher conversion efficiency of ingested food and lower relative consumption rate, their relative growth was faster, indicating stronger food utilization capability. However, they had a lower accumulation of protein. This suggests that different rice varieties had different levels of oxidative stress after infestation by C. medinalis. The defense response of YY1540 was more intense, which was not conducive to the development of the larvae population. These results will provide new insights into the interaction mechanism between different rice varieties and C. medinalis and provide a theoretical basis for cultivating rice varieties resistant to this pest.

中文翻译：

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不同水稻品种的防御反应对稻纵卷叶螟幼虫生长性能和食物利用的影响

摘要

稻纵卷叶螟（Guenée）是水稻上最严重的害虫之一。目前，化学防治是防治该害虫的主要方法。但乱用化学杀虫剂具有非针对性作用，并可能造成环境污染。此外，稻瘟病菌的卷叶行为可能会间接降低化学喷雾的效果。因此，培育高效抗该害虫的水稻品种至关重要。此前的研究发现，中早39号（ZZ39）、秀水134号（XS134）和甬优1540号（YY1540）三个不同的水稻品种均受到不同程度的稻纵卷叶螟侵染。但目前尚不清楚这种差异的原因是否与三个水稻品种对稻瘟病的防御能力差异有关。为了探讨这个问题，本研究调查了三个水稻品种对四龄稻米生长性能和食物利用能力的影响。进一步，根据叶片生理生化指标的差异及其对种群发生的影响，阐明了不同水稻品种防御反应的差异。结果表明，取食YY1540后幼虫成活率最低，且发育期显着延长。这与三个水稻品种的叶蜡、色素和营养成分的差异无关，也与幼虫的摄食偏好无关。超氧阴离子产生率、过氧化氢含量和三种保护酶活性与幼虫成活率呈负相关，且均以YY1540叶片最高。与其他供试品种相比，取食YY1540的幼虫虽然摄食食物转化效率较高，相对消耗率较低，但相对生长较快，表明食物利用能力较强。然而，它们的蛋白质积累较低。这表明不同的水稻品种在被稻瘟病菌侵染后具有不同程度的氧化应激。YY1540的防御反应较为强烈，不利于幼虫种群的发育。这些结果将为不同水稻品种与稻纵卷叶螟之间的相互作用机制提供新的见解，并为培育抗稻纵卷叶螟的水稻品种提供理论依据。